Telephone



H." EIEGGER Dec. 2; 1 921.

TELEPHONE Filed March 24 1921 2 Sheets-Sheet 1 I. l. I I E h'ql II/[IIII I I H. RIEGGER I TELEPHONE Filed March 24, 1921 2 Sheets-Sheet -2 Patented Dec. 2 1924.

- UNITED STATES PATENT OFFICE.-

HANS RIEGGER, F IBERLIN-CHARLOTTENBURG", GERMANY, ASSIGNOR TO SIEMENS & HALSKE, AKTIENG-ESELLSCHAFT, OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A

GERMAN CORPORATION.

' TELEPHONE.

Application filed March 24, 1921. Serial No. 455,374.

To all whom it may concern:

Be it known that I, HANS RIEGGER, a citizen of the German Empire, residing at Berlin-Charlottenburg, Germany, have invented certain new and useful Improvements in Telephones, of which the following is a specification.

My invention refers to telephones and more especially to loud-speaking telephones and its particular object is to provide such telephones with diaphragms of superior efficiency. I attain this end by employing in connection with a telephone a diaphragm having the shape of a ribbon or strip and l fix this diaphragm in its seat by its longitudinal edges.

A diaphragm of this shape ofiers considerable advantages as compared with diaphragms of equal size and of the usual types, especlally with circular diaphragms. A circular diaphragm of larger diameter'than those used for ordinary telephones would have to be much thicker, in order to retain the usual number of 800 to'"1000 vibrations.

As is well known to those skilled in the art, it is advisable not to go too far below this number, if a clear and natural reproduction shall be attained. On the other hand, in order to secure the necessary clearness of speech, the telephone diaphragm .must have a rather considerable damping, which can however be obtained only with difliculty, if owing to an increase of thickness the vibrating mass becomes too large.

Such an increase of thickness also has the further detrimental eflect of reducing the amplitude of the vibrations, although the energy be the same. As a consequence, less energy is imparted to the air.

It is of no use either to increase the strength of the speaking current without changing the size of the diaphragm; for there are limits to the a plication of induced magnetism, and if t e latter becomes too strong in relation to the permanent magnetism, su erimposed vibrations of a very anwing c aracter are liable to occur.

- en employing a diaphragm according to m invention there is no need to increase its t ickness, and the relative strength of induced and permanent magnetism may remain the same as with the usual. type of places and therefore the number of natural,

vibrations remain the same.

The speaking, strength may be further increased by arranging the strip-shaped diaphragms at an angle relatively to one another in such manner, that the! air will vibrate with greater intensity. Care must be taken, however, that the phase-displacement of the sound waves meeting in the centre be not greater than a; quarter wave length, which, within the rangesof speech, amounts to approximately 8 cm.

In the drawings afixed to this specification and forming part thereof a number of telephones embodying my invention are illustrated diagrammatically by" way of ex- I ample. In these drawings Figs. 1 and 2 are transverse and longi; tudinal vertical sections respectively. of a telephone provided with a. single diaphragm,

Fi s. 3 and 4 are a section and plan, respectively, of a telephone comprising an annular diaphragm and electromagnet,

'lFigs. 5 and 6 are longitudinal vertical sections of two more modifications.

Figs. 7 and 8 are longitudinal and trans- I verse vertical sections respectively of a tele phone ,having diaphragms disposed on three sides of a quadrangular prism.

Figs. 9 and 10 are vertical sections of two further modifications comprising diaphragms disposed at a pointed angle relatively to one another, and

Figs. 11 and 12 are a cross-section and side-elevation, respectively, of a telephone comprising a large number of diaphragmsarranged on the sides of a polygon.

Referring to Figs. 1 and 2 of the draw- I in the dia hra 1 is clamped between th wooden fi ame and the mouth piece 3, its length exceeding its width considerably.

The shape of the magnets 4 and 5 corresponds to the shape of the diaphra (Fig. 2). The magnets may be replaced, owever,

/ by a number of single magnets of the usual round type, arranged side by side. The lines of force emanating from the magnets 4 and 5, are closed by the bottom-plate 6.

In the modification shown in Figs. 3 and 4 the diaphragm has an annular shape. The mouth piece is shaped accordingly consisting of an outer shell 8 in the shape of the frustrum of a cone, and of a cone shaped inner part 9. The sound waves generated by the diaphragm are carried along by these two parts in such a way, that they are able to spread uniformly and without disturbing 10 one another. The space confined between them is shaped so as to intensify as much as possible the air pressures produced by the vibrations of the diaphragm, thereby emitting a maximum of energy. The two magnets 12 and 13 are concentric annuli, the winding 14 being laid around the inner magnet 13. The casing consists of the outer portion 10, the inner cylindrical portion 11 and the bottom-plate 15 closing the lines of force emanating from magnets 12 and 13, as indicated by the arrow-in Fig. 3. In the modification disclosed in Fig. 5 the diahragm has the shape of a cylinder-shell.

, ere again the sound waves are guided through a mouth piece of special configuration so as to spread without disturbing one another. This mouth-piece comprises the parts 17 and 18, which are similar to those described with reference to Figs. 3 and 4:. The diaphragm 16 is excited by cylindrical pairs of eleetro-magnets 19 of the usual form arranged closely side by side. Rings v 20 and 21 and the cylindrical shell 22 form the casing.

In the modification illustrated in Fig. 6 the diaphragm 23 has the shape of the envelope of a cone and the mouth piece is formed again of two conical parts 24 and 25. The diaphragm 23 is excited by individual pairs of magnets 26, placed side by side;

the individual parts 27, 28, 29 of the cas-" ing are in the shape of the envelopes of cones.

Owing to their convex shape the diaphragms in Figs. 5 and 6 are stifler than plane diaphragms. They may therefore either be made correspondingly thinner or their diameter maybe increased to such an extent, that the increase in stiffness does not,

' practically, come into account.

In the arrangement disclosed in Figs. 7

and 8 the ribbon-shaped diaphragms 20, 21 and 22 are arranged on three faces of a rectangular prism in suchmanner that the distance between their centre lines does not exceed a quarter wave length; they are set vibrating by magnets 16,17 and 18 whose windings are inserted in one circuit. The long stretched cross-sectional area of the 50 magnets corresponds to the ribbon shape of the diaphragmj In the cavity formed by the diaphragms' the air pressures produced by the vibrating diaphragms are added one to the-other. and the sound thus amplified travels through the mouth piece, there being no opportunity that any disturbing interferences, might arise since the phase displacement of the sound waves arriving from the difi'erent diaphragms cannot be greater than a quarter wave length at the most.

In the modification shown in Fig. 9 two ribbon-shaped diaphragms 26 and 27 are disposed at an acute angle to one another, the distance between their centre lines not exceeding a quarter wave length. The diaphragms are set vibrating by magnets 28, 29, whose windings are inserted in one circuit. The amplified sound produced spreads in the mouth piece 30, the longitudinal section corresponding to that shown in Fig. 7. While care must be taken that the distance between the centre lines of two diaphragms does not exceed a quarter wave length, there is no other restriction in regard to the arrangement of the diaphragms; they may be arranged to form polyhedrons or any ir regular forms, such as shown for instance in Fig. 10.

In the modification illustrated in Figs. 11 and 12 the ribbon-shaped diaphragms 31 are arranged in a circle and the air-waves produced are conducted towards the centre through channels 32, the pressures meeting here so as to produce an intensified sound which canpropagate through the opening 33. As all sound waves arrive at the centre with the same phase, no disturbing interferences can occur. This is true also in case that the distance between the centre lines of two diaphragms is larger than a quarter wave length. However, the length of the ribbon shaped diaphragms themselves should not exceed this, distance. For each diaphragm a magnet 34 is provided, all the magnets being fixed to a common annular rim 35, their windings being connected in parallel or in series, as desired.

My invention may be applied also to sub marine telephony.

I claim:

1. In a telephone the combination of at least one ribbon shaped diaphragm fixed at its longitudinal edges and electromagnetic means adapted to vibrate the diaphragm.

2. In a telephone, the combination of a plurality of ribbon shaped diaphragms fixed at their longitudinal edges and disposed at an angle to one another in such manner that the distance between their center lines does not materially exceed eight centimeters and electromagnets adapted to vibrate said diaphragms.

3. A telephone comprising a plurality of ribbon sha d diaphragms fixed at their longitudinal edgesand dis osed so as to form the sides of a prism an eleetromagnets adapted to vibrate said diaphragms.

4. Atelephone comprising a plurality of ribbon shaped diaphragms fixed at their long udinal edges and disposed so as to form the sides of a prism the cross section of the prism having the form of a re ular polygon and electromagnets adapte to ular polygon and means for conductingt e 1 vibrate said diaphragms. sound Waves produced by said diaphragms 5. In. a telephone the combination of a to the centre of said pol gon.

plurality of ribbon shaped diaphragms fixed In testimony whereof afiix my signature. at their longitudinal edges and disposed so HANS RIEGGER.

as to form the sides of a prism the cross section of the prism having the form of a re 

